During the last decade, a number of studies have been conducted by various investigators in the design, modeling and testing of solar assisted heat pump systems (SAHPSs). This paper reviews the studies conducted on the energy and exergy analysis of SAHPS systems in Turkey and around the world as of the end of December 2004. The studies undertaken on the SAHPS systems are categorized into four groups as follows: (i) SAHPSs for water heating, (ii) SAHPSs with storage (conventional type) for space heating, (iii) SAHPSs with direct expansion for space heating, and (iv) Solar-assisted ground source heat pump greenhouse heating system (SAGSHPGHS). This paper investigates the studies on SAGSHPs, especially ground-source heat pumps, also known geothermal heat pumps, at the Turkish universities in more detail, by giving Turkey's solar energy potential. (c) 2006 Elsevier Ltd. All rights reserved.